mccullooh



(No Model.) 5 sheets-sheet 2. J. MGCULLOCH.

ROCK DRILL.

Patented Jan. 26, 1897.

m rens no. wvoumm wAsnmmoN. n.1;A

J. MGCULLOGH.

'ROCK DRILL. Y 1 No. 575,970. Patented Jan. 26, 1897.

lA/3 I' f (No Model.) 5 Sheets-Sheet 4.

J. MGGULLOGH.

BooK DRILL.

NQ. 575,970. v Patented Jan. 26, 1897.

(No Model.)

` 1 5 sheets-sheet 5. `J. MOGULLOCH. BooK DRILLl No. 575,970. Patented73.71.126,V 1897;4

M22 M i f M-Wr UNITED STATES PATENT OFFICE.

JAMES MCCULLOCH, OF VVOLVERHAMPTON, ENGLAND.

ROCK-DRILL.

SPECIFICATION forming part of Letters Patent No. 575,970, dated January26, 18.97'. Application filed September 30, 1895. Serial No. 564,185.(No model.) Patented in England September 17, 1894,11'0. 17,659.

' ain, residing at Bella Vista, Wolverhampton,

England, have invented certain new and useful Improvements inRock-Drills, (for which I have obtained a patent in Great Britain, No.17,659, dated September 17, 1894,) of which the following is aspecification, reference being had to the accompanying drawings.

My invention relates to rockdrills, and comprises the improvementshereinafter described.

According to one part lof my invention I provide improved means forpreventing the rotation of the twistbar during the backward stroke ofthe drill. The chief feature of this part of my invention relates to theprovision of a twist-bar which can move axially as well as rotate in thedrill-casing. It is by the axial movement of the twist-bar that thelocking and unlocking of the said bar is effected.

According to other parts of my invention I provide an improved hol'derfor the tool or bit and an improved device for easily and readilyclamping the drill-casing at any desired angle.

My invention further comprises improved means for taking up slack due tothe wear of the guides, feed-screws, and nuts of the rockdrill and forlessening the jar given to the operator by the shocks caused by therecoil of the drill.

My invention also has as a further object the construction of animproved valve for controlling the admission and exhaust of the workingfluid. An important feature of'this part of my invention is the novelmeans which I employ to actuate the valve bythe working fluid in thecylinder.

In order that my invention may be clearly understood, I will nowdescribe the same with reference to the accompanying drawings, in which-Figure lis a longitudinal central section through the drill-casing andparts contained therein. Fig. 2 is a transverse section taken on theline m a: of Fig. 1. Fig. 3 is a section on the line gj y, Fig. 2. Fig.4 is a central longitudinal section through the rear end cover of thedrill-casing, showing a modication hereinafter described. Fig. 5 His alongitudinal section through the cylinders for operating the valve,showing a modification hereinafter described. Fig. G is an elevation ofmy improved holder for the bit or tool. Fig. 7 is a section on the linee' ,e of Fig. (i. Fig. S is a central transverse section of my improvedclamp. Fig. 9 is a plan, and Fig. 10 is Ia side elevation, of the clamp.Fig. 11 is a side elevation of a portion of the drillcasingshowing thedevice for preventing the wear of the guides. Fig. 12 is a transversesection of a modified form of valve and ports.

A is the drill-casing.

B is the twist-bar.

C is the piston of the drill.

I provide the rear end of the twist-bar with a head B, having teeth orprojections B2, of any suitable form, secured thereto or formedintegrally therewith. The said head works in a chamber A0, formed in therear end cover of the drill-casing, and is capable of a limited axialmovement in said chamber to lock and unlock the twist-bar. D is atoothed gear so fitted to the said rear end cover of the casing A thatit cannot turn. It is adapted to engage with the teeth B2 when thetwist-bar is in its rearmost position. IVhen the teeth B2 are engagedwith the gear D, the twist-bar B cannot rotate in either direction.

At the commencement of the forward stroke of the drill the frictionbetween the twist-bar B and the twist-nut F of the piston C, throughwhich the twistbar passes, causes the latter to move forward, whereuponthe teeth Bzbecome disengaged from the gear D and the twist-bar is thenfree to rotate. backward stroke of the drill the twist-bar is movedbackward by the friction between it and the tw-ist-nut and its teeth B2are caused to rengage with the stationary gear D, by which means thetwist-bar is again locked. The drill will thus be caused to turn duringits backward stroke, but will be free to move without turning during itsforward stroke.

During the y I sometimes provide that the working fluid in the cylinderA shall assist the friction be'- tween the twist-nut F and the twist-barB to disen gage the teeth B2 from and rengage the same with thestationary toothed gear D. For this purpose I provide suitable passagesIOO or channels GG' in the casing. The channel G communicates with theport leading to the rear end of the cylinder and with the space betweenthe gear D and head B', and the channel G' communicates with thecylinder at a point near the forward end thereof and with the chamber A0at a point in front of the head B'. During the forward stroke of thedrill the working fluid enters the passage G and acts on the rear faceof the head B of the twist-bar, thus causing the said head and bar tomove forward. During the backward stroke of the drill the fluid en tersthe passage G' and acts on the front face of the twistbar head and socauses the bar to move backward. In this manner the twist-bar is lockedduring the backward stroke of the drill and unlocked during the forwardstroke.

I sometimes form the teeth B2 on a conicalshaped head B', adapted toengage with a correspondingl y conical-shaped gear l), as sh own in Fig.4.

My improved holder E, Figs. G and `7, for the tool, drill, or bit isprovided with a keyway E', formed in the side of the socket in which thetool or bit H is held. The said keyway is made of increasing depth fromthe forward to the rear end, and it is fitted with a correspondingtaper-key or wedge J. At the rear end of the key is an extension J',that projects through an' opening in the rear end of the holder. Bystriking the end of the extension J' the tool will be wedged tightly inthe holder and be thereby very firmly held in position. It can be easilyreleased again by striking the opposite end of the wedge, which projectsfrom the front end of the holder.

Figs. 8, 9, and lO illustrate my improved clamp for easily and readilyfixing a rockdrill to work at the different angles required. It isconstructed as follows, that is to say: The clamp, which can slide androtate on the bar or stand of the rock-drill, is furnished with a fixedjaw L and a movable jaw L', between which is received the projectingfoot A2, Fig. l, provided on the cradle A2 of the rock-drill. A taperedkeyway M is formed in the clamp, and a wedge N, sliding in the saidkeyway, serves for tightening the clamp on the bar. A stud N',whichprojects into a slotor groove N2 in the wedge N, serves to prevent theaccidental loss of the wedge.

The hole P that receives the bar of the rock-drill is not trulycylindrical, but about half the area of the hole, and preferably thatpart in which the keyway for the wedge is located forms part of acylinder of .larger diameter than the remaining portion of the hole, asshown in Fig. 8. The clamp can then be' readily applied to and tightenedon a bar which is not truly cylindrical and which does not iit the holeP in the clamp. The necessity of having a truly cylindrical bar isthereby avoided. The jaw L' of the clamp is pivoted at L2 and issupported by a conical bolt O, which fits an inclined curved recess L2,formed in the back of the jaw. The ends of the bolt O are parallel orcylindrical and they are received in lugs or ears O', formed on the bodyof the clamp. One end of the bolt is screw-threaded and screws inio thecorresponding lug O' for the purposes of adjustment.v Vhen the bolt isscrewed into the clamp, the jaw L' is pressed tightly against the footA3 of the cradle A2 of the drill,which is thereby rmly secured betweenthe two jaws. By unscrewing the bolt O the foot of the cradle is againreleased.

O2 is a chain attached to the bolt to prevent loss of the same.

Figs. 2 and l1 show my improved means for taking up slack due to thewear of guides, feed-screws, and nuts in a rock-drill, and also forlessening or preventing the jar occasioned at the handle of theoperating mechanism by the recoil of the drill. According to this partof m yimprovemen ts I construct the feed-nuts Q, Fig. 2, for thefeed-screw R and the bushes Q' Q', Figs. 2 and 1l, for the guide R' of aconical shape and split them longitudinally at Q2. The said nuts Q andthe bushes Q' Q' are received in corresponding conical recesses S S,formed in projecting parts or lugs T T of the drill-casing.- The largeends of the conical bushes and nuts face each other, as indicated withrespect to the bushes in Fig. ll. I interpose a spiral spring U betweenthe bushes Q' Q' on the guide R' and a similar spring between the feed-nnts Q, which are on the otherside of the casing and not shown in Fig.11. The spiral springs U operate to deaden or diminish the force of theshock or jar and to automatically take up any slack in the aforesaidnuts and bushes.

In carrying into practice that part of my invention which relates to animproved valve for controlling the admission and the exhaust of theworking fluid to the cylinder A' of the drill I construct the valve V,Figs. l and 2, of cylindrical form, and I arrange it to work in acylindrical chamber W, formed in the drill-casing A. The axis of saidchamber is preferably perpendicular to the direction of motion of thepiston C.

The chamber W forming the valve-seat is in the construction shown inFigs. l and 2 provided with three openings or ports NV' W2 W2 in thewall thereof. The port W' communicates with the fluid-chest WVO. Theother two ports W2 W3 communicate by passages one to one end and theother to the other end of the workin g cylinderA'. The valve V isprovided with eXhaust-ports V' V2, that communieate with a common outletV4, and it is also provided with an admission port or passage V3. Theports are so arranged that in one position of the valve, as shown in thedrawings, Fig. l, a communication is opened between the port W3,leading` to one end of the cylinder A', and the fluid-chest IVO throughthe passage V3 in the valve, while the port W2,

IOO

IIO

leadin-g to the other end of the cylinder, is openv to the exhaustthrough the port V' in the valve. In another position of the valve thefluid-chest W'J is in communication with that end of the cylinder whichwas before open to exhaust and the opposite end of the cylinder is opento exhaust.

It is obvious that the exhaust from the cylinders Z Z' takes placesimultaneously with that from the two ends of the working cylinder A'.

In a modification shown in Fig. l2 the valve chamber or seat has sixopenings or ports in the side thereof. Two of the said ports-viz., W'and Wij-communicate directly with the iiuid-chest W0, the two ports XV?and W3 communicate with the opposite ends of the working cylinder A', asbefore, and the two remaining ports V4 and W5 are exhaust-ports.

The valve is provided with ports V', V2, and V3, of which V' and V2 arein communication with one another. -The passages are so arranged that inone position of the valve, as shown, a communication is opened betweenthe port W3, leading to one end of the cylinder A', and the fluid-supplyport V3, while the port W2, leading to the other end of the cylinder, isopen to the exhaust-port W5 through the ports V' V2 in the valve. Inanother position of the valve the port TV3, which was formerly opened tothe supply-port V3, is then opened to the second exhaust-port IV, andthe port W2, which was in communication with the exhaust-port lV, isopen to the supplyport V3. Hence when the motive fluid is being admittedto one end of the cylinder the other end of the cylinder is incommunication with the exhaust. On the valve being turned to its secondposition the working fluid is admitted to the opposite end of thecylinder and the first-named end is opened to the exhaust.

For working the valve I provide small cylinders Z Z', Fig. 3, havingpistons c c' working therein and also having ports or passages a ct',which communicate with the working cylinder A'. The valve is providedwith wings or arms cl d', that project above the pistons c c' and thatare operated by said pistons when the latter move up and down. When thepiston C in the Working cylinder'A' approaches the end of its forwardstroke, it uncovers the passage ct and allows the working iiuid to enterthe cylinder Z and act on the small piston c therein. The said piston cis thereby raised and caused to act on the arm d of the valve and thusturn the valve. W'hen the piston O in its backward stroke uncovers theother passage ct', (the passage ct being then closed,) the piston c' ofthe cylinder Z' is raised and caused in the same manner to turn thevalve Vin the opposite direction. The ends of the passages d a.'indicated by dotted lines in Fig. l are really in front of the plane ofsection.

I sometimes provide only one arm or wing d on the valve, as shown inFig. 5, and I then place the two cylinders Z Z' on opposite sides of thesaid arm, so that the pistons c c' of the cylinders Z Z' may actalternately on the said arm, but in opposite directions.

I may employ more than two cylinders such Y as Z Z'. y

rPhe arinsor projections are secured or made solid with the valve insuch a manner that the valve will be balanced and will only alter itsposition when positively operated. Such a vbalanced valve will workequally well in any position and angle at which a rock-drill may berequired to be worked. j

My improved valve is not subject to much or uneven wear, since it has arotary reciprocating motion in place of a sliding reciprocating motion.Moreover, the valve may be easily constructed of such a design as willenable a drill to be made short and light, which are attributes ofespecial advantage in rockdrills.

l. In a rock-drill, the combination with the casing, and thedrill-spindle, of a twist-bar capable of a rotary and a limited axialmovement in the casing, a toothed gear fixed on the rear end of saidtwist-bar, and a non-rotatable, stationary gear D supported in thecasing and adapted to lock the twist-bar when the latter is pushedbackward, and to become disengaged therefrom when said twist-bar ispushed forward or outward, substantially as described. l

2. In a rock-drill, a tool-holder consisting of a head E furnished witha taper-keyway E' smallest at the forward end, and a wedge or key .Iwhich projects from the head at the forward end and hasv a prolongationJ at the rear end projecting through an opening in the rear end of thehead, substantially as described.

3. 1 In a rock-drill, the combination with the casing and cradle, of aclamp havinga key- `way M in the opening P for the drill-bar, the key N,the fixed jaw L, the movable jaw L' having in its back the recess L5,and the bolt O working in the lugs O' to support and adjust said movablejaw between which and the fixed jaw is received the foot of the cradle,substantially as described. Y

4. In a rock-drill, the means for taking up slack due to the wear of thefeed-screws, guides and bushes, and for preventing jar at the handle ofthe operating mechanism, said means consisting of split conicalfeed-nuts Q for the feed-screw and bushes for the guides, received inconical lugs formed on the drillcasing and having their large endsfacing each other, and a spiral spring interposed between said largeends substantially as described.

5. In asrock-drill, a balanced circular valve V adapted to oscillate ina valve-chamber without gland or bushing about an axis at right anglesto the axis of the working cylin-l uder, wings or arms integral with thevalve, pistons c, c' adapted to control the said arms IOO IIO

In testimony whereof I have hereunto set my hand this 5th day ofSeptember, 1895.

JAMES MOCULLOCIT. Vtn esses:

SIMON ROBERTS, VILLIAM G. COOPER.

